I have not read every message in this thread so excuse me if this has been covered but I'm on OS X and when I am running BT I sit at:
0.2 KiB/s dn
Then I fire up Tommatoe torrent and begin a same .torrent download file, my original BT application will spike up to like 50 or 60 KiB/a then fade back down to 0.2
